1. Field of the Invention
The present invention relates to an endoscope apparatus, and more particularly to an endoscope apparatus that picks up an image of light that includes a plurality of wavelength band components.
2. Description of the Related Art
Endoscope apparatuses have been conventionally used in a medical field for purposes such as observing the inside of a body cavity of a subject. More specifically, an endoscope apparatus used in the medical field has a configuration that, for example, includes a light source apparatus that supplies an illuminating light that is irradiated onto a site to be observed inside a body cavity, an endoscope that picks up an image of return light that is generated accompanying irradiation of the illuminating light onto the site to be observed inside the body cavity, and an image processing apparatus that generates an image of the site to be observed based on the return light for which an image was picked up by the endoscope.
Further, many endoscope apparatuses having the above described configuration adopt an image pickup method that is one of a frame-sequential image pickup method and a simultaneous image pickup method.
More specifically, the aforementioned frame-sequential image pickup method can be realized, for example, by a configuration in which an image of return light that is generated when frame-sequential light obtained by subjecting illuminating light including a plurality of wavelength band components to time division is irradiated onto a site to be observed is picked up by an image pickup device in which a color filter is not provided on an image pickup surface.
The aforementioned simultaneous image pickup method can be realized, for example, by a configuration in which an image of return light that is generated when illuminating light including a plurality of wavelength band components is irradiated onto a site to be observed is picked up by an image pickup device in which a color filter in which a plurality of minute filters that are each equipped with a predetermined spectral sensitivity characteristic are disposed in a predetermined arrangement is provided on an image pickup surface.
For example, Japanese Patent Application Laid-Open Publication No. 2008-036035 discloses an endoscope apparatus that adopts the aforementioned simultaneous image pickup method.
In this connection, generally, each filter included in the aforementioned color filter is configured to have a spectral sensitivity characteristic that transmits not only light of a predetermined color component, but also light of a wide band from a visible region to a near-infrared region.
More specifically, for example, an R filter included in a common Bayer array RGB color filter is configured to have a spectral sensitivity characteristic that transmits not only red light but also a part of blue light and green light.